Friday, March 20, 2015

To vaccinate or not to vaccinate against YFV?

A woman who was planning a trip to South America received the Yellow Fever vaccine, and developed a rare serious reaction to the vaccine. The woman was healthy and in her 60s. About a week after receiving the vaccine, she entered the ER with a severe vomiting, diarrhea and shortness of breath. The condition worsened, while she was at the hospital, presenting as heart damage and acute kidney failure. She died after she had been in the hospital for three days. The autopsy showed that she had noticeable levels of virus in several organs, but the autopsy also showed an undiagnosed tumor in her thymus, a special organ of the immune system responsible for the maturation of T cells. After the autopsy, the doctors declared her diagnosis was yellow fever vaccine-associated viscerotropic disease, a serious reaction to the vaccine in which the virus replicates in the body; they also added that her thymus could have contributed to the progression of the disease. Yellow fever vaccine-associated viscerotropic disease is an extremely rare disease affecting 4 out of every 1,000,000 vaccine administrations. People are at a greater risk of developing a complication or a more serious outcome if they are over 60 years of age and if they have problems with their thymus. Unfortunately this woman fit into both risk groups, and if her physicians had known about the cancer, they would not have proceeded with the vaccination.

The CDC maintains the position that travelers should research the vaccines they want to take, evaluate the chances of exposure in their desired destination, research the disease, and the quality of the health services in the travel destination. In response to this event the MMWR wrote, “Although most persons have no or mild adverse events after yellow fever vaccination, the benefits of vaccination among travelers who have a limited exposure period need to be weighed against risk for adverse events.” As some food for thought the CDC reported that in a certain period of time, 5 people developed serious reactions to the vaccine while 4 unvaccinated people died of yellow fever. It’s all a matter of knowing all the facts and making an informed decision.